Karyotyping through Image Analyzing System in two species of Nigella (family: Ranunculaceae) revealed 4 (N. sativa: 2n=12=4A+4B+2C+2D; karyotype formula: 2L1smsc+2L1m+2Lsm+2Lm+2Mm+2St) and 3 (N. damascena: 2n=12=6B+4C+2D; karyotype formula: 4Lmsc+2Lm+4Mm+2St) morphologically distinct chromosome types (L1=very long ≥15.0 μm, L=long 13.0 to <15.0 μm, M=medium 7.0 to <13.0 μm, S=short <7.0 μm, m=metacentric, sm=sub-metacentric, t=telocentric and sc=satellites). The somatic chromosome complements in the species formed graded karyotypes which were symmetric in nature (TF%: N. sativa 42.90, N. damascena 40.62). Total haploid chromatin length was noted to be 78.622 μm in N. sativa and 70.136 μm in N. damascena.
The effect of clarithromycin on the induction of chromosome aberrations in mice bone-marrow, splenocyte cells and spermatocyte cells was investigated. Male Swiss mice were orally treated by gavage once with doses 50, 100, 200 and 300 mg kg−1 b.wt. A repeated daily dose of 50 mg kg−1 b.wt. was given for successive days. Clarithromycin induced chromosome aberrations in both bone-marrow and splenocyte cells. The percentage of chromosome aberrations was found to be statistically significant after single and repeated treatments. The percentage of chromosome aberrations in diakinesis–metaphase I spermatocytes increased in a dose dependent manner and was found to be statistically significant after 2 higher and repeated doses. The high doses of the antibiotic caused a significant increase in the frequency of sister chromatid exchanges in mice bone-marrow. Its highest values were 9.99±0.48/cell after treatment with high dose (300 mg kg−1 b.wt.) compared with 4.24±0.44/cell in the non treated mice.
A detailed analysis of the karyotype and the meiotic behavior of the South American endemic Lathyrus hasslerianus is provided in this study. The karyotype obtained is the most asymmetrical of section Notolathyrus, which together with the particular morphological characters and ecological requirements supports a derived state of this species. Meiotic analysis showed the occurrence of univalents and out of plate bivalents in metaphase I, which ultimately leads to the formation of micromicrospores or micronuclei at the sporad stage. Mechanisms of aberrant sporad formation are discussed. Even though, pollen viability was reduced, it does not compromise the species fertility as shown by the analysis of the seed set.
Karyotypes of the A and B genomes of Musa L. were prepared using a technique involving squashing of 0.02 M hydroxyquinoline-treated and HCl-fixed root tips. The wild diploids had 2n=22 chromosomes. Mitotic metaphase chromosomes of both the AA (‘Calcutta 4’, M. accuminata Colla) and BB (‘Butohan 2’, M. balbisiana Colla) taxa ranged from 1.4 to 3.6 μm in length and showed great similarity in structure and size. The genomic chromosome complement in a somatic cell of the 2 species was made up of 10 metacentric, 6 submetacentric, 4 subacrocentric and 2 acrocentric chromosomes. The 2 largest submetacentric chromosomes in each of the diploid species had secondary constrictions. The 2 species did not show obvious differences in their karyotypes.
To efficiently transfer important disease and insect resistance traits from diploid Mexican wild species Solanum pinnatisectum to tetraploid cultivated Solanum tuberosum, molecular cytogenetic and karyotypic analyses were carried out to examine the degree of chromosomal and genomic variation between these 2 species. The results demonstrated that the chromosome complement in S. pinnatisectum was predominantly metacentric and submetacentric, while S. tuberosum showed prominent subtelocentric and telocentric chromosomes. It appears that karyotype evolution from diploid to tetraploid originates through chromosome rearrangements, involving mainly deletions or multiplication at the same ploidy level. Fluorescence in situ hybridization (FISH) using 18S-5.8S-26S ribosomal RNA (rDNA) as a probe demonstrated that both diploid and tetraploid potato species had a single nucleolus organizer region (NOR) locus. However, the localization of the rDNA sites in one of the 2 accessions of S. pinnatisectum was characterized by a pair of morphologically distinct chromosomes, in which one was a submetacentric chromosome, while its homologous partner was a subtelocentric chromosome, which was very similar to that observed in tetraploid potato. This indicated that chromosome variation in structural alterations and nuclear DNA content, as well as loss or addition of highly repetitive sequences could play a role in potato evolution and development of new cultivars. This study offers a useful molecular cytogenetic marker for species identification, chromosome inheritance and potential introgression in future intergenetic hybridization experiments with Mexican wild potato species.
Paramphistomes are intestinal parasitic warms infecting a wide range of vertebrate animals and are considered, by various authors, as the most primitive digenetic trematodes. The karyotypes of Sandonia sudanensis McClelland, Basidiodiscus ectorchis Fischthal and Kuntz inhabiting a common fish host, and Synodontis schall Bloch-Scheinder were studied. We recorded that both Sandonia sudanensis and Basidiodiscus ectorchis have the same number of chromosomes with diploid number 2n=12 and n=6 at the end of meiotic divisions. As far as the authors know, the present work is the first chromosomal study of these 2 fish paramphistomes and the first karyological observation of fish-infecting paramphistomes. The results are discussed and compared with that of mammalian paramphistomes.
The antitrypanosomal drug Diminazene aceturate (Berenil) was investigated to assess its genotoxic effect through different cytogenetic parameters. Male swiss mice were intraperitoneal (i.p.) injected with therapeutically relevant doses 3.5, 7 and 10.5 mg kg−1 b.wt. for 1, 3, 5 consecutive days. Berenil increased frequencies of micronucleus in polychromatic erythrocytes especially with high and repeated doses, indicating an aneugenic action. Moreover, marrow toxicity was observed as indicated by significant percentage of chromosome aberrations in bone-marrow cells at all treatment doses. Gaps, fragments and breaks were found to be the most sensitive types of structural aberrations. Polyploidy is a characterized phenomenon of numerical aberrations in treated somatic cells. With respect to germ cells Berenil at the same doses induced high significant percentage of chromosome aberrations (P<0.01) in lry spermatocytes after i.p. treatment with 10.5 mg kg−1 b.wt. for 3 and 5 consecutive days. However, Berenil showed a low influence on sperm abnormalities. Percentage was significant at low level (P<0.05) after the treatment with the highest dose. In conclusion, the different cytogenetic parameters indicate its genotoxic effect on the genome of somatic and germ cells especially at multiple doses.
Rhizome yield, 4C nuclear DNA content and RAPD analysis were carried out of 17 promising cultivars of turmeric (Curcuma longa L.). The rhizome yield per plant varied significantly from 77.66 to 350 g among 17 cultivars of Curcuma longa. Significant variation of 4C DNA content was recorded at the intraspecific level with values ranging from 4.30 to 8.84 pg. The differential DNA content observed among 17 different cultivars of Curcuma longa comprising same (2n=48) chromosome number could be attributed to the loss or addition of highly repetitive sequences in the genome. Random amplified polymorphic DNA (RAPD) analysis clearly revealed genetic variation among 17 cultivars of turmeric showing differential polymorphism using 20 primers. The amplification fragments per primer ranged from 4 to 17 in 17 cultivars with fragment size ranging from 0.4 kb to 3 kb. Intraspecific polymorphism ranged from 35.6% to 98.6% among 17 cultivars studied. The RAPD primers OPN06 and OPA04 having strong resolving power were able to distinguish all 17 cultivars. The extent of genetic diversity among 17 cultivars was computed through Nei's genetic similarity and genetic distances. The genetic variations detected through 4C nuclear DNA content and RAPD analysis have significance for turmeric improvement programmes.
Callosobruchus maculatus (Coleoptera: Bruchidae) is a stored grain pest of Vigna radiata (L) (Mung) and shows polymorphisms in males as well as females. These polymorphs are differentiated on the basis of colour pattern of elytron and pygidium. The genomic DNA of all these polymorphic forms has been analysed using RAPD-PCR technique with 2 random decanucleotide primers. Primer-12 (5′-AAGAGCCCGT-3′) and primer 17 (5′-TGCCGGCTTG-3′) which amplified variable number of distinct bands revealing bands unique to each form and common bands among them depicting the genetic variations as well as similarities at molecular level and a diagnostic band common to all abnormal forms is also obtained.
The karyotype and C-banding analysis of somatic metaphase chromosomes were attempted on 3 species of Indian frogs (Rana curtipes, R. temporalis, R. malabarica) which are distributed in the Western Ghats, Southwest India. All had 2n=26 chromosomes with invariably 5 pairs of large and 8 pairs of small chromosomes. Metacentric and submetcentric chromosomes were found in the complement, the former more common than the latter. A secondary constriction with a prominent satellite in the short arm of nos. 10 and 12 chromosomes are unique only in R. curtipes. The C-positive telomeric bands were localized in the short arms of nos. 9 and 10 chromosomes of R. temporalis. Non-centric C-positive bands were observed in the distal half of the long arm of no. 10 chromosome of R. malabarica. None of the 3 species had an identifiable sex chromosome. There were variations in the centromeric position and secondary constriction of chromosome pair nos. 2, 3, 4, 5, 9, 11 and 12. These variations might have arisen due to pericentric inversions. It seems likely from the inversion studies that R. curtipes and R. temporalis are chromosomally more closely related than R. malabarica. Comparative account of karyotypes are discussed.
A cell division-inducing factor (CDF) purified from the culture filtrates of auxin autotrophic 2B-13 cells induced semi-synchronous cell division in auxin-starved tobacco BY-2 cells. The CDF was identified as a glycoprotein, whose polypeptide chains have been found to have homology to ATP-binding cassette (ABC) transporters, while its sugar moiety has not yet been characterized. Specific binding of the CDF to several types of lectins suggests that the sugar moiety of the CDF is composed of mannose and/or galactose. Furthermore, specific binding of the CDF to β-glucosyl Yariv reagent suggests that the CDF has certain characteristics of arabinogalactan proteins. Intriguingly, the addition of increased amounts of β-glucosyl Yariv reagent to the culture medium inhibited 2,4-D induced cell division of auxin-starved BY-2 cells, suggesting that the CDF plays a pivotal role in inducing cell division in the auxin signaling pathways.
Karyotype analysis of 7 species of Echinopsis of the tribe Cereeae of the family Cactaceae revealed significant interspecific variations. The diploid chromosome number 2n=22 was found in all the studied species. Significant variation in total genomic chromosome length, volume and in 4C DNA content in the root tip cells was recorded. The nuclear DNA content varied from 7.353 pg in E. werdermanii to 10.353 pg in E. eyerisii; new record on genome size. Correlation coefficient analysis confirm the significant correlation between chromosome volume and nuclear DNA content. Interspecific variation evident in the structural alteration of the somatic chromosome along with genome size suggested the species-specific variations of genomic organization through the variation in repetitive DNA sequences of the species.
RAPD-PCR technique has been employed to study the genetic similarities and diversity in 2 species of butterflies namely Pieris brassica and P. indica (Family: Pieridae) using 2 decamer primers i.e. P12 and P17. Though both the primers yielded a series of bands, but P12 failed to give any amplification in P. indica individuals. P17 also yielded low number of bands in this species. Both primers produced 2 types of patterns. Type I bands were shared by both the sexes, while type II were unique to either male or female individuals. The data was relevant to facilitate the calculation of the band sharing coefficient (D).
Comparative phylogenetic studies of rhesus monkey (Macaca mulatta) and human (Homo sapiens) using G-banding patterns were investigated. Blood samples of rhesus monkeys were examined using lymphocyte culture technique. The results indicate that the number of diploid chromosome of rhesus monkey is 42. The types of autosomes are 18 metacentric and 22 submetacentric chromosomes. The short arm of chromosome pair 13 is a satellite chromosome. The X and Y chromosomes are metacentrics and the smallest metacentric chromosome, respectively. Five chromosome pairs, 5, 12, 13, 19 and X, have the same G-banding patterns as human chromosomes. The short arm of chromosome pair 13 is identical to the chromosome pair 22 and the long arm is identical to the chromosome pair 15 of human. The results infer that the chromosome pairs 15 and 22 of human are derived from the splitting of chromosome pair 13 of rhesus monkey or the chromosome pair 13 of rhesus monkey is derived from the fusion of chromosome pairs 15 and 22 of humans. Additionally, G-banding patterns of 11 chromosome pairs, 1, 3, 6, 7, 8, 9, 10, 11, 14, 17 and 20 of rhesus monkey and humans are similar. The chromosome pair 1 of rhesus monkey and human is pericentrically inverted which is derived from alternate connection of centromeric chromosome. G-banding patterns of 6 chromosome pairs, 2, 4, 15, 16, 18 and Y are different from human chromosomes. The results show that there is a common evolutionary relationship between rhesus monkeys and humans.